1. Field of the Invention
The invention relates to a perforated support plate for supporting and injecting fluids into a bed of packing elements in treatment towers or vessels and particularly for a gas-liquid contact apparatus.
2. Description of the Prior Art
Various support systems and plates are known for supporting beds of packing elements in fluid-fluid, liquid-liquid and gas-liquid contact apparatus or towers. Such apparatus being towers designed to bring two counter flowing mediums in contact to effect a specific treatment such as transfer of heat from one to the other.
Present packing support systems utilize sections with vertical or inclined and horizontal perforated portions in the general configuration of a beam to support packing. The essentially vertical portion will pass the upward flowing gas and is in the upper portion of the beam. The perforated horizontal or essentially horizontal portion will pass the liquid phase which flows downward and is in the lower section of the beam. By having the liquid and gas separate and pass different openings the pressure drop across the support system is reduced compared with support systems where the liquid and gas pass common openings in a counter current direction. The present systems have three general limitations.
First: The physical load from packing may be limited by the vertical or inclined perforated wall portion. If this portion is overloaded the side panels or walls will deflect inward and cause failure either structurally or from a flow handling characteristic or both.
Secondly: Around the perforated openings are relatively sharp edges which cause resistance to entrance and flow through the openings. This adds to the gas phase pressure loss of the support system.
Thirdly: The perforated vertical portion of the beam which must shed the down-coming liquid and allow the openings to remain free for the up-coming gas to pass through have essentially flat surfaces and the gas flow must keep the liquid from entering the perforations. Thus, some pressure must be lost by the gas to keep liquid from entering the perforations. This adds to the gas phase pressure loss of the support system.
The present invention greatly improves on all three of these limitations by smoothly flaring and raising the edge of the material around the perforated openings. This will add ribs and rigidity to the side panels to prevent inward deflections. Each entrance to the openings is smoothly rounded which reduces the resistance to flow, or in effect provides a higher orifice coefficient. Exits of the openings with relatively sharp edges are beyond the side panel and the down-coming liquid will be mostly restricted from entering from the exit of the opening and thereby decreases the resistance to the gas flow.
U.S. Pat. Nos. 3,222,040 and 3,419,253 granted to John S. Eckert and assigned to the assignee of this application and Design Manual TA-70 entitled, Packed Tower Internals published by Norton Chemical Process Products Division, Akron, Ohio 44309, copyright 1970 disclose packing support plates similar in many respects to and of the type with which the instant invention concerns itself.
However, this invention is an improvement over comparable prior art perforated support plates known to the applicant and differ therefrom in that the apertures providing the free or open space in the walls thereof have around them smoothly curved entrances and projecting rims or wall portions which improves directional flow characteristics of the counter flowing mediums, lowers the resistance to flow and thereby reduces the pressure drop across the support system. Also, the walls in each section of the support are strengthened by the projecting rims and have, depending on rim size, up to eight (8) times more resistance to bending or deflection than nonrimmed apertured walls of a comparable support section of identical size, shape and amount of free or open space. Hence, the support plate assembly has a much greater load supporting capacity in cases where the walls are limiting.